Telephone-exchange.



C. L. REDFIELD. TELEPHONE- EXCHANGE.

APPLICATION FILED FEB. 13, 1905.

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C. L. BEDFIELD.

TELEPHONE EXCHANGE.

APPLICATION FILED FEB. 13. 1905.

Patented June 6; 1916.

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TELEPHONE EXCHANGE. APPLICATION FILED FEB. 13. 1905.

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T EEC TELEPHONE-EXCHANGE.

Specification of Letters Patent.

Patented June 6, 1916.

Application filed February 13, 1905. Serial No. 245,409.

' To all whom it may concern:

Be it known that I, CASPER L. REDFIELD, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Telephone- Exchanges, of which the following is a specification.

My invention relates to telephone exchanges and more particularly to party line exchanges and has for its object the simplification of the mechanism and wiring of such exchanges and the arrangement of devices whereby party line exchanges may be operated without the intervention of a central telephone oflice.

In the accompanying drawings :Figure 1 is a plan view of mechanism secured to the inside of the cover of a telephone box, the upper part being removed on the section line 11 of Fig. 3; Fig. 2 is a section on line 22 of Fig. 1; Fig. 3 is a section on line 3-3 of Fig. 1; Fig. 4 is a section on line 44 of Fig. 2; Fig. 5 is a section on line 5-5 of Fig. 2 showing the devices back of the ratchet wheel; Fig. 6 is the same as Fig. 5 with the shield or guard plate removed; Fig. 7 is a diagram showing two telephone stations connected to a party line; Fig. 8 is an additional diagram showing three stations connected together by one wire and ground.

In the said drawings B is the cover of a telephone box to the inside of which is secured a plate B by means of posts B Supported in B and B is a shaft or spindle C on the outer end of which is an arm C Mounted on the spindle C bet-ween the cover B and the plate B is a ratchet wheel C. A pawl C pivoted at C and engaged by a spring C prevents the ratchet wheel C from moving backward and furnishes a slight resistance to its movement in the direction of the arrow in Fig. 4.

Secured to the plate B is a bracket B and secured by one end to the bracket B is a spindle D, the other end of which spindle is turned down and is guided in a socket in the spindle C, as shown in Fig. 2. Loosely mounted on the spindle D is a ratchet wheel D the back face of which bears against a washer J which is held against ashoulder on the spindle D by the nut J Between the washer J and the nut J 2 are a shield or guard D and a soft .washer .J- The se parts are so arranged that the shield is held I.

by a slight friction between the washers J and, J The amount of this friction may be regulated by adjusting the nut J 2 and is normally enough to hold the shield in the place to which it is moved while at the same time offering resistance enough to prevent it from being freely moved to another position. The guard D is in the form of a sector pivoted upon the spindle D and provided with two short flanges D and D which project laterally closely adjacent to the teeth of the ratchet wheel D Supported on the plate B is a polarized magnet A, whose armature A is provided with a pawl A adapted to engage and turn the wheel D On a post E is a holding pawl E held in contact with the wheel D by the spring E Also on the post E is a lever provided with arms F, F and F A spring F acts to turn the lever so as to move the arm F against an adjustable stop F. In the arm F is a pin F adapted to be engaged by a notch C in the lever C when the arm F is against thestop F, but is normally held clear of the lever C as shown in Fig. 6.

The ratchet wheel D is normally held in the position shown in Fig. 1 by a spring D shown in Fig. 3. Secured to the wheel D are pins D and D In the normal position of the wheel'the pin D engages the arm F to press the pin F out of the 'path of the lever C on the spindle C, and also engages the edge of the guard D to move it so that the flanges D and D will have the relationship to the pawls E and A that is shown in Fig. 1. In this position the pawls are free to engage the teeth of the ratchet wheel D W'he n, by the action of the magnet A, the pawl A advances the ratchet wheel, the pin D leaves its contact with the arm F and permits the spring F to move the pin F into the path of the arm G on the spindle 0, thereby preventing its subsequent movement and consequently the movement of the indicating arm C and the ratchet wheel C A continued movement of the ratchet wheel D results in bringing the pin D into contact with the edge of the guard D moving it so that its flanges D and D are pushed under the pawls E and A In this position the wheel D is released from its pawls and is permitted to return to its normal position under the action of the spring D Upon its return to normal position the pin D strikes the guard D moving its flanges clear of the pawls so that they may reengage the wheel.

It also strikes the arm F moving the pin F clear of the arm C so that the indicating arm C is again free to be moved.

On the inside face of the plate B is a ring 12 provided with a series of inward projections 12. Insulatingly secured to the ratchet wheel C is a contact maker 13 adapted to make electrical contacts with the projections 12 when the arm C is turned. When in its normal position the contact maker 13 rests on a contact point 15 located between two projections 12 On the outer face of the telephone box cover B is a ring B on which may be placed a series of numbers indicating the several stations on the party line and located in the path of the arm C The ratchet wheel C and its pawl C the contact maker 13 and the projections 12, and the arm C and the numbers of the dial ring B are so related to each other that the wheel and its pawl tend to stop the arm C at one of the numbers on the dial, and the contact maker between two projections 12*.

Insulatingly secured to the ratchet wheel D is a contact maker 24, in the path of which are contact posts or points 25 and 27. The contact point 25 is located so that the contact maker 24 makes electrical connection with it when at its normal position. For different stations on the party line the contact points 27 are different distances from the normal positions of the contact makers 24.

At each station in addition to the mechanism described, there is an ordinary telephone set consisting of generator G, polarized ringer Q, receiver R, hook H, transmitter T, induction coil K, batteries X and Y, and certain contact points and connections as shown in the diagrams in Fig. 7 and 8. Instead of having a separate battery X at each station as shown in Fig. 8, one battery X may be used at one end of the line and an extra wire run between stations as shown in Fig. 7 or the two ways of connecting may be used on the same party line as would be in the case by considering Figs. 7 and 8 twoparts of the same system.

The operation is as follows :Assuming that the subscriber at station No. 3 wishes to talk with the one at station No. 5, he would turn his indicating arm C to the figure 5 on his dial B, turn the crank of his generator G, remove his receiver R, talk, return the receiver, and move the indicating arm C the rest of the way around to its normal position. The called subscriber does no more than remove and return his receiver.

The movement of the arm C at station No. 3 breaks the connection between 13 and 15, and immediately thereafter makes it between '12 and 13, when a current flows as follows :X-Y121314ground at number 3 to ground at the other stations on y the line 14l31516A1718 back to station No. 322X. This is a current cor responding in direction with the polarity of the magnets A and causes them to move their respective contact makers 24 forward one step. At the next contact between 12 and 13 the movement is repeated, and as the arm C was moved to the number 5 on the dial the connection would be repeated five times and all of the contact makers 24 (except the one at the calling station) would be moved forward five steps. As the contact points 27 are arranged for position to correspond to the numbers given the stations, only the contact maker 24 of station No. 5 would be on its contact point 27. As the current through the magnet A goes through its contact point 15, and as the connection to this point is broken at the calling station by the movement of the contact maker 13, it is evident that the contact maker at this station will not be moved but will remain in connection with the contact point 25, which is connected by line 26 with point 27.

When the generator is operated the current flows as follows :G2021-18 to station No. 52223242728Q, 29-30H-14ground back to No. 3 1431-G. This calls the subscriber of sta tion No. 5 who removes his receiver, when the talking circuit is as follows: K of No. 3-33R3435 H-14ground to numbcr 5 14H3534R33-K- 32 2827-24-232218 back to No. 3- 22232425-26272832-K.

When the rest of the rotation of the arm C is made after hanging up the receiver the remaining contacts between 12. and 13 move the ratchet wheels D far enough to cause the pins D at the several stations to strike their guards D causing the release and the return of the ratchet wheels to their normal position as hereinbefore described. The distance between the edge of the guard D and the pin D which strikes it is equal in number of teeth of the wheel D to the maximum number of stations that it is intended to put on the party line. As the last contact between 12 and 13 represents a release of the operating mechanism and not a stop for a station, it is-evident that the ring 12 would have one projection more than the number of stations represented, and it may be used in that way. I may however add' one or two extra contact projections, the contacts between which and the contact maker 13 would occur in the interval between the actual release of the wheel D and its arrival at its normal position.

In the operating current flowing through the magnets A there are branches from 14 through H and the ringers Q, but this current flows in a direction contrary to the polarity of the ringer magnets and consequently does not affect them. Likewise in the ringing circuit there are branches from 18 through the magnets A but the flow of the ringing circuit is contrary to the polarity of the operating magnets. In Fig. 7 the operating circuit is: X-50-22-12- etc. In Fig. 8 there are only two connections between stations, ground and the wire 18. In Fig. 7 there are three connections, ground and the wires 18 and 50, the talking being through ground and 18. It-will be obvious that by substituting ground connections for the wire 50, and a wire for the present ground connections there would be a complete metallic circuit for talking.

It will be obvious that the present arrangement eliminates the necessity of a central ofiice and reduces the electrical devices at each station to what may be operated by a single magnet. It will also be evident that as soon as one subscriber has moved his indicating arm C and has thereby caused a movement of the devices at the other stations, that the pin F of each of the stations has moved into the path of thearm C and consequently has locked all of the indicating arms C so that they cannot be moved. As a result of this no one not called on the party line can break into a connection established. Whenever it is desirable to connect the party line with some other party lines, any one of the stations on the line may be selected as a central office and be supplied with a switchboard. In such a case the subscriber in that station would perform all of the functions of a central oflice operator while retaining the same apparatus as that used at the other stations.

What I claim is:

1. The combination with a series of switching mechanisms, and a propelling magnet for each, of propelling and holding devices for each mechanism, a releasing device for each adapted to be interposed between the mechanism and its propelling and hold devices, means by which each releasing device is operated by its associated switching mechanism at a predetermined point in its propelled movement, and electrical connections for simultaneously operating said propelling devices.

2. A series of ratchet wheels, a magnet and pawl for moving each wheel, a guard for each wheel arranged to be interposed between sai-d wheel and its driving pawl, means for controlling said guards by the movements of their respective wheels, a contact making device adjacent to each magnet, electrical connections interconnecting the several magnets and contact making devices, and means whereby upon operating one of said contact making devices the adjacent magnet will be cut out from the electrical connections while all of the other magnets will move their respective wheels and interpose their respective guards.

3. A series of switching mechanisms, a propelling magnet for each mechanism, a selecting lever associated with each mechanism and normally serving to close the electrical connection of the propelling magnet therefor, means whereby the movement of selecting lever from its normal position will break the electrical connection for the associated magnet and thereby prevent its operation, and means whereby such movement of the selecting lever will cause an electrical impulse to pass through all of the other magnets.

4. The combination with a series of switching mechanisms, a corresponding series of propelling magnets, and a corresponding series of selecting levers, of means whereby a movement of one of said selecting levers will cut out one of said propelling magnets and cause the operation of all of the other magnets of theseries.

5. The combination with a series of propelling magnets, a corresponding series of selecting levers, and electrical connections for said magnets, of means whereby a movement of one of said levers will break the electrical connections of the corresponding magnet and cause electrical impulses to be sent through the other magnets of the series.

6. The combination with a series of propelling magnets, a corresponding series of selecting levers, and electrical connections for said magnets, of means whereby a movement of one of said levers will break the electrical connections for the corresponding magnet and cause the operation of the other magnets of the series, and means whereby the operation of the other magnets will lock their corresponding levers so as to prevent their movement.

7. A switching mechanism adapted to be advanced from a normal position, devices for releasing the switching mechanism so that it may return to normal position, a selecting lever, means for locking said lever so as to prevent its movement and for unlocking so as to permit its movement, a propelling magnet, and means whereby the pro pelling action of said magnet serves to advance and release said switching mechanism and to lock and unlock said lever.

8. In a telephone station, the combination with a switching mechanism and a selecting mechanism each of which is movable to and from a normal position, of means .whereby a movement of either one of said mechanisms will prevent a movement of the other mechanism until the moved mechanism has been returned to its normal position.

9. In a series of telephone stations, the combination with a selecting device and a switching device located at each station, of means whereby only one of the two devices at a station may be moved at one time, and means whereby the movement of a selecting device at any one of the stations will cause a simultaneous movement of the switching devices of the other stations.

10. In a telephone station, the combination with a selecting device and a switching mechanism mounted upon a common axis, of devices carried by each arranged to cooperate with the other.

11. In the switching mechanism of a local telephone station, a propelling device for moving the switching mechanism from its normal position, devices for releasing the switching mechanism from its propelling device so that it may return to normal position, and means for actuating the releasing devices by the latter part of the forward movement of the switching mechanism. V

12-. In a telephone station, the combination with a selecting device and a switch- Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, 7

ing mechanism, of an electrical connection through which said switching mechanism is operated, and means by which said connection is broken by the operation of said selecting device.

13. The combination with a series of stations, a party line, and a switching mecha nism at each station, of means controlled at any station for moving the switching mechanisms of the other stations so asto connect a selected one telephonically to the party line and to exclude all others, and means also controlled from the same point for releasing the moved switches so as to cause them to move in a reverse direction back to their normal positions.

Signed at Chicago, 111. this 10 day of Feb. 1905.

CASPER L. REDFIELD.

Washington, D. G. 

